In the field of semiconductor devices, large arrays of many semiconductor devices are increasingly used. For example, large arrays of LED pixels are used for lighting or display purposes. LED arrays are useful because of low energy consumption, high reliability, long lifetime, small size, and fast switching speeds. A large array of LED pixels may be controlled by a large array of semiconductor devices, such as driving circuits implemented using current sources and/or power switches.
Testing semiconductor devices is important to ensure their reliability. However, large arrays of semiconductor devices pose some testing issues. Some industries, such as the automotive industry and aerospace industry, have significant testing requirements to ensure reliability and safety. In order to obtain good test coverage, automated test equipment (ATE) systems have become widespread for testing semiconductor devices. Such ATE systems allow testing to be performed quickly and reduce human involvement in the testing, thereby reducing test cost and human error. An ATE system often involves software that controls hardware to perform tests, collect data, and create reports on the operation of the semiconductor devices.
Front end testing for a large array of semiconductor devices can be problematic because of the high number of contacts corresponding to a large number of devices. Back end testing can be problematic because of the high production costs from failed devices that are not discovered until late in production.